This document provides contouring and treatment planning guidelines for stereotactic body radiation therapy (SBRT). It discusses indications, contraindications, simulation, target volume delineation, organ at risk contouring, dose prescription, and plan evaluation for SBRT treatment of lung, spine, liver, and other cancers. Key considerations include ensuring accurate tumor targeting given organ motion, minimizing dose to nearby organs at risk, and prescribing ablative doses in a small number of fractions to achieve tumor control.

1. SBRT Contouring Guidelines
Dr Rushi Panchal,MD
Consultant Radiation Oncologist,
M S Patel Cancer Centre,
Karamsad- Anand, Gujarat
Email id: rusp2582@gmail.com
Mob No.: 09727757165

2. Safe delivery is of utmost importance due to high
fractional dose and small number of fractions

3. Unlike intracranial radiosurgery, where the PTV is immobile within the skull and therefore
relatively easy to fix in relation to the radiation source, at extra-cranial sites there are the
problems of internal organ motion and external patient movement

5. serial tissues, the volume-dose
constraints are given in terms of the
critical maximum tissue volume that
should receive a dose equal or
greater than the indicated threshold
dose for the given number of fractions
used. For parallel tissue, constraints
are based on a critical minimum
volume of tissue that should receive a
dose equal to or less than the
indicated threshold dose for the given
number of fractions used.

8. SBRT
• Primary cancer
• Oligometastatic disease” is defined as a state in which metastases
are limited in number and site and characterized by unusual cancer
biology and behaviour(stable tumour state somewhere between
purely localised and widely metastatic) In this setting local ablative
therapy could have a potential curative role.
• in an analysis of over 5000 patients with lung metastases, survival
after complete surgical resection was 36% at 5 years and 22% at 15
years, Pastorino UB et al. J Thorac Cardiovasc Surg
1997;113:37–49.

9. SBRT LUNG

10. Indication
• Patients with T1, T2 (≤ 5 cm), T3 (≤ 5 cm), N0, M0 non-
small cell lung cancer(squamous cell carcinoma, adenocarcinoma, large
cell carcinoma, large cell neuroendocrine, and non-small cell carcinoma not otherwise
specified) patients with T3 tumors must have chest wall
primary tumors only.
• Oligometastasis of lung from primary elsewhere.
the 2-year OS was 60.3% for patients with
1–3 metastases compared with 21.9% for
patients with4–5 metastases

11. Contraindication
• Bronchioloalveolar cell carcinoma

12. Simulation & Contouring
Aspects
However, due to respiratory
motion, standard free-breathing
computed tomography both distorts
and generally underestimates the
tumour volume therefore, GTV on
a single free-breathing computed
tomography scan is both an
inaccurate representation of the
tumour dimensions and of the
mean tumour position relative to
other organs

14. Simulation & Contouring
Aspects

18. • Supine
• CT Scan: IV Contrast
Non 4 D CT:The PTV will include the GTV plus an
additional 0.5 cm margin in the axial plane and 1.0 cm
margin in the longitudinal plane (craniocaudal).
4D CT-simulation: An internal target volume (ITV)
around the GTV, accounting for tumor motion may be
defined from the 4D CT dataset. The PTV will include the
ITV plus an additional 0.5 cm margin uniformly applied to
the ITV.
• Slice thickness : ≤ 3.0 mm
• OAR Contouring as follows:
Simulation & Contouring
Aspects

19. OAR Contouring

22. Dose prescription & Plan evaluation

23. Dose prescription & Plan evaluation

24. Dose prescription & Plan evaluation

25. • As per TG 101 for 1/3/5# protocol
• 4 fraction protocol as follows:
Constraints

26. Premedication
• Although not mandatory, it is recommended that patients
receive corticosteroid premedication (e.g.,
Dexamethasone, 4 mg, p.o. in a single dose, or
equivalent) 15-60 minutes before each SBRT treatment
for the intended purpose of modulating immediate
pulmonary inflammatory effects.
• Analgesic premedication to avoid general discomfort
during long treatment durations also is recommended
when appropriate

27. SPINE
SBRT

28. Indication
• Patients with localized spine metastasis from the C1 to
L5 levels (a solitary spine metastasis; 2 separate spine
levels; or up to 3 separate sites); each of the separate
sites must have a maximal involvement of 2 contiguous
vertebral bodies. (e.g. C5, T5-6, and T12)?
• ≥5 NRPS(Numerical Rating Pain Scale) of at least one of
the planned sites for spine radiosurgery
• Zubrod Performance Status : 0-2
• Patients with epidural compression are eligible provided
that there is a ≥ 3 mm gap between the spinal cord and
the edge of the epidural lesion.
• A paraspinal mass (≤ 5 cm in greatest dimension),
contiguous with the spine metastasis

29. There can be multiple small metastatic lesions
shown in other vertebral bodies as shown in
diagram (4) above. The metastatic lesion of
each spine should be less than 20% of the
vertebral body as opposed to the diffuse
vertebral involvement. These small lesions are
often seen in the MRI even when bone scan or
PET was negative. Most of these lesions are not
clinically required to be treated and are
therefore not included in the target volume. Only
the painful spine (pain score≥ 5) is to be
treated .

30. Contraindication
• myeloma or lymphoma
• Non-ambulatory patients
• spinal instability due a compression fracture
• > 50% loss of vertebral body height
• Frank spinal cord compression or displacement or
epidural compression within 3 mm of the spinal cord
• Rapid neurologic decline
• Bony retropulsion causing neurologic abnormality
• Prior radiation to Index Spine
• Patients for whom an MRI of the spine is medically
contraindicated

32. Points to remember
• Patients can have other visceral metastasis, and radioresistant
tumors (including soft tissue sarcomas, melanomas, and renal cell
carcinomas) are eligible
• MRI (contrast is not required but strongly recommended) of the
involved spine to determine the extent of the spine involvement; an
MRI is required as it is superior to a CT scan in delineating the
spinal cord as well as identifying an epidural or paraspinal soft
tissue component.MRI can be used as the required MRI for
treatment planning.
• Patients with mild to moderate neurological signs are eligible. These
neurological signs include radiculopathy, dermatomal sensory
change, and muscle strength of involved extremity 4/5 (lower
extremity for ambulation or upper extremity for raising arms and/or
arm function).
• Imaging study(bone scan, PET, CT scan, or MRI)

33. Simulation & Contouring
Aspects
• Supine
• Immobilized with vacuum bag, alpha cradle, or
stereotactic frames, for cervical spine or cervicothoracic
junctional areas, a rigid head and neck immobilization
• CT-MRI Fusion T1 PC, T2
For soft tissue tumor & Cord
• <3mm slice thickness

34. Target Volume delineation

35. Target Volume delineation
In any circumstance, when there is an epidural or paraspinal soft tissue tumor component, the visible
epidural or paraspinal tumors are included in the target volume

36. Target Volume delineation

37. Target Volume delineation
Anterior VB with no epidural extension
Left pedicle, posterolateral VB, and neural
foramen. Involvement of the ventral and left lateral
epidural space, mild spinal canal compromise, and
abutment of the spinal cord
Collapse deformity, ventral epidural disease,
moderate spinal canal compromise, mild spinal
cord displacement, extension to the bilateral
neural
foramina, and paraspinal extension
Pedicle and posterior elements, mild ventral and
right lateral epidural disease narrowing of the right
neural foramina
Centered in the spinous process and extending to
the bilateral lamina, bilateral posterior paraspinal
musculature, and bilateral dorsal epidural space
extension with mild spinal canal compromise

38. Target Volume delineation
Expansile mass in right-sided VB and right posterior
elements with mild right ventral, lateral, and dorsal
epidural disease Involvement of the right neural
foramina
Posterior VB lesion extending into the left neural
foramen with mild spinal canal compromise and left
ventral and lateral epidural extension
Lesion in posterior VB
Diffuse marrow replacement including left pedicle and
articular facets, ventral epidural extension, left lateral
recess extension, and left neural foramen
involvement
Lesion with mild superior and inferior endplate
infractions resulting in mild loss of VB height. Mild
anterior paraspinal extension. Patient underwent
T5 kyphoplasty

39. OAR Contouring

40. Dose Prescription & Plan
evaluation
• 16-18Gy/1# or 24Gy/3#
• >/=90% coverage of the target volume by the prescribed
dose( up to 80% is minor deviation)
• 80-90% isodose line is used as prescription line
• Dose inhomogeneity can exist within the target volume
• Outside of the target : >/= to 105% Dose to less than or
equal to 2.0 cc (3cc is major violation)
• >/= to 105% dose to a region within 1.0 cm(1.5 cm is
major violation) from the edge of the target volume
• excludes all doses of greater than or equal to
110%(115% is major violation) of the prescription dose
outside of the target volume.

41. Any spinal cord dose exceeding these constraints is not acceptable and is a major deviation.
Radiosurgery is not recommended for any cases that do not meet the spinal cord constraints. Each
CT slice within the Radiosurgery plan should be checked to screen any unacceptably high radiation
dose to the spinal cord at any particular slice. In this situation, stopping the Radiosurgery or to
perform re-planning. Other Critical organs should be analyzed for radiation dose distribution if any of
them are transected by any radiation field. Exceeding these limits by more than 2.5% constitutes a
minor violation. Exceeding these limits by more than 5% constitutes a major deviation

42. Constraints
maximum dose limits
to a point or volume
within several critical
organs

43. Premedication
• Not must but can be added
• Analgesic
• Anxiolytic
• Steroid

44. SBRT LIVER

45. Indication for HCC SBRT
• Unsuitable for resection or transplant or radiofrequency
ablation (RFA)
• Unsuitable for TACE or refractory to TACE
• Barcelona Clinic Liver Cancer Stage (BCLC)
Intermediate (B) or Advanced (C)
• Often used in 1-3 lesions, could be considered for larger
lesions or more extensive disease if there is sufficient
uninvolved liver and liver radiation tolerance can be
respected.
• Child Pugh A/ Early Child Pugh B.

47. Contraindication for HCC SBRT
• Any one hepatocellular carcinoma > 15 cm
• Total maximal sum of hepatocellular carcinoma > 20 cm
• More than 5 discrete intrahepatic parenchymal foci of HCC
• Direct tumor extension into the stomach, duodenum, small bowel or
large bowel
• Measureable common or main branch biliary duct involvement with
HCC
• Extrahepatic metastases or malignant nodes (that enhance with
typical features of HCC) > 2.0 cm, in sum of maximal diameters
(e.g. presence of one 2.4 cm metastatic lymph node or two 1.2 cm
lung lesions). Note that benign non-enhancing periportal
lymphadenopathy is not unusual in the presence of hepatitis and is
permitted, even if the sum of enlarged nodes is > 2.0 cm
• Hepatic insufficiency resulting in clinical jaundice, encephalopathy
and/or variceal bleed.

48. Age is not considered in selection criteria, as even elderly and fragile patients
can safely undergo SBRT. This non-invasive and well-tolerated therapy is a
good option for patients unsuitable for surgery.
The intrinsic radio-sensitivity of tumours is not an issue ,as SBRT can be used
regardless of histopathology thanks to the use of ablative doses, with similar
local control rates in radioresistant and radiosensitive primary tumour.

49. Prerequisite
• For all patients, the following criteria calculated from baseline CT or
MR scans should be met:
•  Liver volume minus intrahepatic GTV > 700 cc.
•  Intrahepatic tumor GTV/liver volume ratio <80%.
•  Minimal distance from GTV to stomach, duodenum, small or large
bowel > 1 cm.

50. Simulation & Contouring
Aspects HCC
• Supine
• Custom immobilization is recommended (e.g. With vacuum
immobilization, patient positioning boards, knee cushions, and/or
breath hold immobilization with active breathing control).

51. Simulation & Contouring
Aspects HCC

53. • The primary tumor(s) and any tumor vascular thrombi must be treated
• The Gross Tumor Volume (GTV) is defined as all parenchymal and vascular
HCC visualized on contrast enhanced CT and/or MRI, most often best seen on
arterial phase (as hyperintensity) and/or venous or delayed phase (as hypointensity
relative to liver). Vascular HCC thrombi (GTVv) most often are best seen on venous
phase imaging as hypointensity relative to the contrast in the vessel, Vascular HCC
may be combined with parenchymal HCC (labeled as GTVp or GTVpv) if they are to
be treated to the same dose.
• Treatment of non-tumor extrahepatic vascular thrombi, RFA cavities and prior TACE
sites is not recommended. no prophylactic nodal irradiation is allowed.
• It is expected that there will be no expansion from GTV to CTV for the majority
of cases. However, CTV expansions to include regions at high risk for microscopic
disease, including non-tumor vascular (v) thrombi (CTVv), prior TACE (t) sites (CTVt),
or adjacent RFA (r) (or other ablation) sites (CTVr) are permitted.
• PTV will provide a margin around each CTV to compensate for set-up and
internal organ motion
• minimum PTV margin of 4 mm around each CTV is required in all directions (for
example if active breathing control is used with excellent reproducibility). The
maximum permitted PTV margin is 20 mm, expected to be used uncommonly. PTV
margins ≤ 10 mm are a goal.
Target Volume delineation for
HCC

54. OAR Contouring for HCC
• At minimum, these structures are required to be contoured at the
level of the PTV and over any region received > 10 Gy.
• An upper abdominal/liver atlas, posted at the ITC website, may be
used as a guide for contouring.
• all portions of the duodenum are recommended to be contoured

56. Dose Prescription & Plan
evaluation for HCC
• 27.5 Gy - 50 Gy in 5 fractions. The prescription dose may be 50 Gy,
45 Gy, 40 Gy, 35 Gy, 30 Gy or 27.5 Gy in 5 fractions, based on
normal tissue constraints.
• The dose to multiple PTVs may be different.
• The goal is to use the highest allowable prescription dose to the
primary target, while respecting normal tissue constraints. The
minimal planned prescription dose to PTVs is 27.5 Gy.
• The prescription isodose should encompass 95% of PTV. The dose
to multiple PTVs within the same patient may vary, with each
specific covering isodose planned to encompass 95% of each PTV.
The highest allowable doses to the target volumes that
maintain normal tissue constraints should be used. A goal is
that 100% of the CTV is encompassed by the prescription dose.

57. Dose Prescription & Plan
evaluation for HCC
• Dose prescription: Is based on the volume of normal tissues
irradiated (correlated with mean liver dose), as well as proximity of
stomach, duodenum, small and large bowel (GI luminal structures)
to the target volumes, as normal tissue constraints must be
maintained.
• In the absence of adjacent GI luminal structures that may limit dose,
the PTV dose prescription should be as high as possible based on
mean liver dose (MLD, defined as the mean dose to the liver minus
all GTVs)
• Vascular tumor thrombosis (e.g., portal vein thrombosis) dose
should be the same as the HCC prescription dose. However, lower
doses are acceptable if required to maintain normal tissue limits,

58. Dose Prescription & Plan
evaluation for HCC
• Maximum dose within PTV = 150%. If multiple PTVs exist, 150% of
the maximal PTV prescription dose is permitted for all PTVs
• Maximum dose outside PTV = 120% of the maximal PTV
prescription.
• Efforts should be made to keep the 30Gy isodose as conformal as
possible.
• Different isodoses may cover different PTVs. If multiple PTVs, the
MLD should be evaluated with the prescription dose corresponding
to the highest dose level that any PTV is treated.
• Reducing the maximal dose to all luminal gastrointestinal
normal tissues should be a planning priority to reduce the risk
of gastrointestinal toxicity.

59. Dose Prescription & Plan
evaluation for HCC
3 × 15–25 Gy for patients with tumors <3 cm in size and adequate liver
reserve (CP-A5)
5 × 10–12 Gy for patients with tumors between 3 and 5 cm or inadequate liver
reserve (CP-A 6)
10 × 5–5.5 Gy for patients with tumors >5 cm in size or CP-B scores

60. Constraints for HCC

61. Constraints for HCC

62. SBRT Liver metastasis

63. SBRT Liver metastasis

64. SBRT PROSTATE

65. Indication
• Gleason scores 2-6; Clinical stage T1-2a; PSA < 10
ng/mL (PSA should not be obtained within 10 days after
prostate biopsy)

66. Contraindication
• Evidence of distant metastases
• Regional lymph node involvement
• Previous radical surgery (prostatectomy), cryosurgery, or
HIFU for prostate cancer
• Previous pelvic irradiation, prostate Brachytherapy

67. Simulation & Contouring
Aspects
• Supine with Elekta Body fix / Vacuum Cushion + knee
Rest.
• Planning CT Scan with Axial cuts of 2.5 mm or less will
be acquired throughout the pelvis and prostate from the
top of the iliac crests Superior to the perineum inferior
with full bladder and empty rectum.
• MRI images is not must.
• Oral, IV, urethral, and bladder contrast are allowed but
not required.

68. Target Volume delineation
• GTV = Prostate Only
• CTV = GTV
• PTV = CTV + 5mm margin except
posterior( +/- anterior ) 3 mm

69. OAR Contouring

70. Dose Prescription & Plan
evaluation
• 36.25 Gy/5# 7.25Gy/#. The 5 treatments will be scheduled to be
delivered twice a week over approximately 15-17 days. A minimum
of 72 hours and a maximum of 96 hours should separate each
treatment. No more than 2 fractions will be delivered per week. The
total duration of treatment will be no shorter than 15 days and no
longer than 17 days.
• prescription dose should cover a minimum of 95% of the PTV.
• The minimum dose within the PTV to a point that is 0.03 cc in size
must be ≥95% of the prescribed dose.
• The maximum dose within the PTV is 7% above the prescribed dose
for a point that is 0.03 cc in size.

71. Constraints

72. THANK
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